1. Field of the Invention
This invention is in the field of orthopedics, in which reconstruction through immobilization is a common practice. Traumatic and reconstructive orthopedics is a rapidly increasing area of medicine and plaster immobilization offers the most versatility in this area. Plastic materials are sometimes used but they also require removal in a similar fashion.
Cast cutters are often used in hospital areas and doctor's offices where cleanliness and quiet surroundings are desirable. This invention aids in both aspects. Also the suppression of noise is additionally desirable since a loud sawing operation adds greatly to the factor of fear in the patient, especially with younger children.
The use of plaster casts for immobilization is often bypassed by orthopedists and other physicians due to the difficulties and dangers of removal. The advantages of plaster immobilization are often overcome by the inherent difficulties in removal. Plaster casts could be a more attractive remedy if cast removal were an easier and safer operation.
2. Description of the Prior Art
The prior art instruments for cutting casts present many difficulties. Firstly, the motor for driving the blade is located in the hand-piece, which makes it heavy and cumbersome. Since the hand-piece is usually held by one hand of the operator, the additional weight of the motor will induce fatigue if operated for any length of time.
Locating the motor in the hand-piece also increases the noise therefrom in the neighborhood of the patient. This is especially undesirable with smaller children, which is a prominent age group utilizing cast immobilization.
Another problem of the prior art is the generation of heat in the neighborhood of the hand-piece. The friction caused from cutting of the cast by the blade is the primary source of heat but the problem is compounded by the heat generated from the motor when located within the hand-piece. By locating the drive motor remote from the hand-piece and vacuuming in the immediate area of the cutting means the heat generation problem is minimized.
The vacuuming apparatus used in the prior art is inefficient and if cast dust is missed by the main vacuuming opening there is no efficient procedure to clean up the work area without the use of additional apparatus.
The blades used in the prior art tend to become dull quickly since they are cutting through the rather hard cast material currently used. So it would be desirable to have a means for sharpening the blade while located within the hand-piece, and more particularly for automatically sharpening the blade during a cast cutting operation.
The hardness of currently used cast materials requires a large amount of force to be applied to the cutting blade by the operator. Consequently the operator must maintain a very strong grip upon the hand-piece during a cutting operation. The hand-piece of the presently used instruments is coaxial with the axis of oscillation of the cutting blade. This arrangement fails to take into account the 30.degree. backward tilt of a person's hand with respect to his arm when in the strongest grasping position, the powergrip. When the powergrip is made on the presently used hand-piece, the angle of the blade with respect to the arm makes such a grip unusable and an alternate less powerful grasp must be used.
In hospitals there are very often high local concentrations of oxygen in the atmosphere, which can result from overflow or leaks from iron lungs, oxygen tents, oxygen masks and the like. Thus, the danger of fire due to sparking of electric motors is considerable. It is, therefore, desirable to provide a means for shielding the motor drive means from the hospital atmosphere. Such an apparatus would be especially adaptable to modern buildings where wall sockets are often provided in each room for vacuuming and various types of power sources are provided similar to common electrical wall sockets.
The current state of the art in hand-pieces for use in cast cutting is shown by the following patents:
Patentee Patent No. ______________________________________ Hawley 1,093,049 Haushalter 1,542,128 Blair 2,043,028 Staunt 2,098,317 May 3,136,021 Seegers 3,147,551 Burglaff 3,173,207 ______________________________________
These patents relate to various dental tools and other grinding instruments which show arrangements of placing a vacuuming opening in close proximity to a cutting or grinding bit. None of these patents has any application to the field of art of orthopedics or cast cutting. Also, none of these devices places the cutting means coplanar and at an angle with respect to the holding surface to allow for the particular anatomical configuration of the operator. The dental tools show the grinding surface as not coaxial with the hand-gripping surface but this relationship is required by the configuration of the patient's mouth and not by the anatomical requirements of the operator. A dentist is not required to grip his instruments powerfully.